An umbrella is made by stitching 10 triangular pieces of cloth of two different colours each piece measuring 30cm, 60cm, 60cm. How much cloth of each colour is required for Umbrella?
s = $$\ \frac{\ a+b+c}{2}$$ = $$\ \frac{\ 30+60+60}{2}$$ cm =75 cm
Using Heron's formula
Area=√[s(s-a)(s-b)(s-c)]
=√[75(75-60)(75-60)(75-30)]
=$$225\sqrt{\ 15}$$ cm
There are total 10 pieces
First colour=5*($$225\sqrt{\ 15}$$) = $$1125\sqrt{15}$$ cm
Second colour=5*($$225\sqrt{\ 15}$$) = $$1125\sqrt{15}$$ cm
B is the correct answer.
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